spatial_weights_matrix function

Create a spatial weights matrix

Creates a spatial weights matrix by multiplying an adjacency (connectivity) matrix (see connectivity_matrix()) and an edges weights matrix (see edges_weights_matrix()). Resulting spatial weights equal to 0 will be replaced by 4 x max(w), where max(w) is the maximal weight in the matrix.

spatial_weights_matrix(x, y)

Arguments

• x: an adjacency matrix of dimensions n x n, where n is the number of nodes (sites). The output of connectivity_matrix().
• y: an edges weight matrix of dimensions n x n, where n is the number of nodes (sites). The output of edges_weights_matrix().

Returns

A spatial weights matrix of dimensions n x n, where n is the number of nodes (sites).

Examples

# Import Adour sites ----
path_to_file <- system.file("extdata", "adour_survey_sampling.csv", 
                            package = "chessboard")
adour_sites <- read.csv(path_to_file)

# Select the 15 first sites ----
adour_sites <- adour_sites[1:15, ]

# Create node labels ----
adour_sites <- create_node_labels(adour_sites, 
                                  location = "location", 
                                  transect = "transect", 
                                  quadrat  = "quadrat")

# Create edges based on the pawn move (directed network) ----
adour_edges <- create_edge_list(adour_sites, method = "pawn", 
                                directed = TRUE)

# Get connectivity matrix ----
adour_adjacency <- connectivity_matrix(adour_edges)

# Convert sites to sf object (POINTS) ----
adour_sites_sf <- sf::st_as_sf(adour_sites, 
                               coords = c("longitude", "latitude"),
                               crs = "epsg:2154")

# Compute distances between pairs of sites along the Adour river ----
adour_dists <- distance_euclidean(adour_sites_sf)

# Create Edges weights matrix ----
adour_weights <- edges_weights_matrix(adour_dists)

# Create Spatial weights matrix ----
spatial_weights_matrix(adour_adjacency, adour_weights)